This is not a stupid question.
An itchy scalp can be the result of dry skin, allergies to ingredients, product build up, and far less common, a medical condition.
Oil is used to SEAL IN moisture, not to moisturize. Perhaps your scalp was dry (as in, needed water) and the oil is sealing that moisture out? Generally, I like to spritz my scalp before adding oil to be sure that I'm addressing the problem and not adding to it.
Is your scalp dry frequently? Then I would suggest drinking more water, herbal teas, etc to hydrate your skin from the inside out. I would also refrain from frequently using conditioners and shampoo directly on the scalp until you find a balance that works for you. Lastly, I would spritz with water and seal with a light oil.
I hope that helps!